發(fā)布時間：2018-12-06 22:10

【摘要】：近年來，隨著經(jīng)濟的發(fā)展和城市建設(shè)的不斷擴展，橋梁的跨徑在不斷的增大，橋梁形式也變得多種多樣，普通的橋型已經(jīng)無法滿足人們的省美以及使用要求，各種大跨徑新型橋梁不斷的被應(yīng)用于城市橋梁的建設(shè)，單索面寬箱梁斜拉橋作為一種新型橋梁，既滿足了城市建設(shè)美觀上的需要，又滿足了城市交通量不斷增大需要，同時還滿足了跨越能力的需要。然而設(shè)計理論的不完美以及施工質(zhì)量的缺陷等各方面的因素，使得單索面寬箱梁斜拉橋很容易在施工過程中產(chǎn)生裂縫，而裂縫的出現(xiàn)對于橋梁結(jié)構(gòu)的受力以及使用是相當不利的，所以，對單索面寬箱梁斜拉橋早期裂縫成因的分析，對于設(shè)計以及施工都是十分有必要的。 本文以重慶雙碑嘉陵江大橋（主跨330米，，箱梁寬32.5米，單索面寬箱梁斜拉橋）為工程背景，該橋在零號塊二次澆筑時，在箱梁的底板、翼緣板及橫隔板上產(chǎn)生了大量的裂縫，不僅影響橋梁的美觀，同時影響橋梁的施工及后期的運營使用，因此本文針對該橋在施工零號塊時底板、翼緣板、橫隔板出現(xiàn)裂縫的現(xiàn)象展開研究分析。 本文首先對單索面寬箱梁斜拉橋的特點進行了一個闡述，對國內(nèi)外關(guān)于橋梁裂縫的分析研究現(xiàn)狀做了一個介紹；然后對重慶雙碑嘉陵江大橋零號塊的裂縫分布情況進行了一個描述，并對橋梁裂縫的產(chǎn)生原因進行了淺要分析；最后分別對自重及索力作用下的效應(yīng)、預(yù)應(yīng)力及掛籃作用下的效應(yīng)、混凝土橫向收縮效應(yīng)對主梁的影響、溫度效應(yīng)對主梁的影響進行計算。在自重及索力作用的計算中， 通過對各種影響因素的計算結(jié)果進行研究分析，對比橋梁裂縫分布的實際情況，總結(jié)出裂縫集中部位的裂縫比率，從而得知各部位裂縫的成因以及引起開裂的主要因素。從各個因素的分析結(jié)果來看，溫度效應(yīng)是引起主梁混凝土開裂的主要因素，溫度在水化熱過程產(chǎn)生了熱量從而使混凝土溫度升高，混凝土溫度升高到一定程度后水化熱的產(chǎn)熱與混凝土的散熱達到平衡，之后便開始降溫，降溫引起混凝土的收縮，因此在混凝土初凝的早期便產(chǎn)生了裂縫。其次收縮是引起主梁混凝土開裂的又一重要因素，新老混凝土的澆筑時間相距過長，使得新澆筑混凝土與老混凝土的收縮速度差距過大，從而約束了新混凝土的變形而產(chǎn)生了裂縫，并且隨著時間的推移，裂縫仍然在發(fā)展。
[Abstract]:In recent years, with the development of economy and the continuous expansion of urban construction, the span of bridges has been increasing, and the forms of bridges have become various. All kinds of long-span new bridges are used in the construction of urban bridges. As a new type of bridge, the cable-stayed bridge with single cable plane and wide box girder meets not only the aesthetic needs of urban construction, but also the increasing demand of urban traffic volume. At the same time, it also meets the need of leapfrogging ability. However, because of the imperfection of design theory and the defects of construction quality, it is easy to produce cracks in the construction process of cable-stayed bridge with wide box girder with single cable plane. However, the occurrence of cracks is quite unfavorable to the force and use of bridge structure. Therefore, it is necessary for design and construction to analyze the causes of cracks in the early stage of cable-stayed bridge with wide box girder with single cable plane. This paper takes the Chongqing Shuangbei Jialing River Bridge (main span 330 meters, box girder 32.5 meters wide, single cable plane wide box girder cable-stayed bridge) as the engineering background. There are a lot of cracks on the flange plate and the transverse spacer, which not only affect the beauty of the bridge, but also affect the construction of the bridge and the operation of the bridge later. Therefore, this paper aims at the bottom plate and flange plate of the bridge in the construction of zero block. The phenomenon of cracks in the transverse diaphragm is studied and analyzed. In this paper, the characteristics of cable-stayed bridge with wide box girder with single cable plane are described, and the analysis and research status of bridge cracks at home and abroad is introduced. Then it describes the distribution of cracks in block zero of Shuangbei Jialing River Bridge in Chongqing, and analyzes the causes of the cracks in the bridge. Finally, the effects of deadweight and cable force, the effect of prestress and hanging basket, the effect of transverse shrinkage of concrete on the main beam and the effect of temperature on the main beam are calculated respectively. In the calculation of deadweight and cable force, by studying and analyzing the calculation results of various influencing factors, comparing the actual situation of bridge crack distribution, the crack ratio of the concentrated part of crack is summarized. Thus, the causes of the cracks and the main factors causing the cracks are known. From the analysis results of various factors, the temperature effect is the main factor that causes the cracking of the main beam concrete, and the temperature produces heat in the hydration heat process, which makes the concrete temperature rise. When the temperature of concrete rises to a certain extent, the heat production of hydration heat reaches equilibrium with the heat dissipation of concrete, and then it begins to cool down, which causes the shrinkage of concrete, so cracks occur in the early stage of concrete initial setting. Secondly, shrinkage is another important factor that causes cracking of main beam concrete. The pouring time of new and old concrete is too long, which makes the gap of shrinkage speed between new and old concrete too large. Therefore, the new concrete deformation is restrained and cracks are produced, and the cracks are still developing over time.
【學位授予單位】：重慶交通大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U448.27

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